Capgras & Fregoli Delusion

The Capgras delusion theory (or Capgras syndrome) is a disorder in which a person holds a delusion that a friend, spouse, parent, or other close family member has been replaced by an identical-looking impostor. The Capgras delusion is classified as a delusional misidentification syndrome, a class of delusional beliefs that involves the misidentification of people, places, or objects. It can occur in acute, transient, or chronic forms.

The delusion is most common in patients diagnosed with schizophrenia, although it can occur in connection with a number of conditions, including brain injury and dementia. It occurs more frequently in females, with a female:male ratio of 3:2. Although the Capgras delusion is commonly called a syndrome, because it can occur as part of, or alongside, various other disorders and conditions, some researchers have argued that it should be considered a symptom, rather than a syndrome or classification in its own right.

The Fregoli delusion or the delusion of doubles is a rare disorder in which a person holds a delusional belief that different people are in fact a single person who changes appearance or is in disguise. The syndrome may be related to a brain lesion, and is often of a paranoid nature with the delusional person believing themselves persecuted by the person they believe is in disguise.

The Fregoli delusion is classed both as a monothematic delusion, since it only encompasses one delusional topic, and as a delusional misidentification syndrome, a class of delusional beliefs that involves misidentifying people, places, or objects. Like Capgras delusion, psychiatrists believe it is related to a breakdown in normal face perception.